mirror of
https://github.com/shaka-project/shaka-player.git
synced 2026-06-18 16:36:56 +03:00
david-hm-morgan
248 lines
8.8 KiB
JavaScript
248 lines
8.8 KiB
JavaScript
/*! @license
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* Shaka Player
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* Copyright 2016 Google LLC
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* SPDX-License-Identifier: Apache-2.0
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*/
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goog.provide('shaka.polyfill.MediaSource');
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goog.require('shaka.log');
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goog.require('shaka.polyfill');
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goog.require('shaka.util.MimeUtils');
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goog.require('shaka.util.Platform');
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/**
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* @summary A polyfill to patch MSE bugs.
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* @export
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*/
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shaka.polyfill.MediaSource = class {
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/**
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* Install the polyfill if needed.
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* @export
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*/
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static install() {
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shaka.log.debug('MediaSource.install');
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// MediaSource bugs are difficult to detect without checking for the
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// affected platform. SourceBuffer is not always exposed on window, for
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// example, and instances are only accessible after setting up MediaSource
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// on a video element. Because of this, we use UA detection and other
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// platform detection tricks to decide which patches to install.
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const safariVersion = shaka.util.Platform.safariVersion();
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if (!window.MediaSource) {
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shaka.log.info('No MSE implementation available.');
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} else if (window.cast && cast.__platform__ &&
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cast.__platform__.canDisplayType) {
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shaka.log.info('Patching Chromecast MSE bugs.');
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// Chromecast cannot make accurate determinations via isTypeSupported.
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shaka.polyfill.MediaSource.patchCastIsTypeSupported_();
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} else if (safariVersion) {
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// TS content is broken on Safari in general.
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// See https://github.com/google/shaka-player/issues/743
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// and https://bugs.webkit.org/show_bug.cgi?id=165342
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shaka.polyfill.MediaSource.rejectTsContent_();
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// NOTE: shaka.Player.isBrowserSupported() has its own restrictions on
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// Safari version.
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if (safariVersion <= 12) {
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shaka.log.info('Patching Safari 11 & 12 MSE bugs.');
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// Safari 11 & 12 do not correctly implement abort() on SourceBuffer.
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// Calling abort() before appending a segment causes that segment to be
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// incomplete in the buffer.
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// Bug filed: https://bugs.webkit.org/show_bug.cgi?id=165342
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shaka.polyfill.MediaSource.stubAbort_();
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// If you remove up to a keyframe, Safari 11 & 12 incorrectly will also
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// remove that keyframe and the content up to the next.
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// Offsetting the end of the removal range seems to help.
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// Bug filed: https://bugs.webkit.org/show_bug.cgi?id=177884
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shaka.polyfill.MediaSource.patchRemovalRange_();
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} else {
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shaka.log.info('Patching Safari 13 MSE bugs.');
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// Safari 13 does not correctly implement abort() on SourceBuffer.
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// Calling abort() before appending a segment causes that segment to be
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// incomplete in the buffer.
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// Bug filed: https://bugs.webkit.org/show_bug.cgi?id=165342
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shaka.polyfill.MediaSource.stubAbort_();
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}
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} else if (shaka.util.Platform.isTizen2() ||
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shaka.util.Platform.isTizen3() ||
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shaka.util.Platform.isTizen4()) {
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shaka.log.info('Rejecting Opus.');
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// Tizen's implementation of MSE does not work well with opus. To prevent
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// the player from trying to play opus on Tizen, we will override media
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// source to always reject opus content.
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shaka.polyfill.MediaSource.rejectCodec_('opus');
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} else {
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shaka.log.info('Using native MSE as-is.');
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}
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if (window.MediaSource &&
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MediaSource.isTypeSupported('video/webm; codecs="vp9"') &&
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!MediaSource.isTypeSupported('video/webm; codecs="vp09.00.10.08"')) {
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shaka.log.info('Patching vp09 support queries.');
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// Only the old, deprecated style of VP9 codec strings is supported.
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// This occurs on older smart TVs.
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// Patch isTypeSupported to translate the new strings into the old one.
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shaka.polyfill.MediaSource.patchVp09_();
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}
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}
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/**
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* Stub out abort(). On some buggy MSE implementations, calling abort()
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* causes various problems.
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*
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* @private
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*/
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static stubAbort_() {
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/* eslint-disable no-restricted-syntax */
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const addSourceBuffer = MediaSource.prototype.addSourceBuffer;
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MediaSource.prototype.addSourceBuffer = function(...varArgs) {
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const sourceBuffer = addSourceBuffer.apply(this, varArgs);
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sourceBuffer.abort = function() {}; // Stub out for buggy implementations.
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return sourceBuffer;
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};
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/* eslint-enable no-restricted-syntax */
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}
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/**
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* Patch remove(). On Safari 11, if you call remove() to remove the content
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* up to a keyframe, Safari will also remove the keyframe and all of the data
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* up to the next one. For example, if the keyframes are at 0s, 5s, and 10s,
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* and you tried to remove 0s-5s, it would instead remove 0s-10s.
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*
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* Offsetting the end of the range seems to be a usable workaround.
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*
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* @private
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*/
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static patchRemovalRange_() {
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// eslint-disable-next-line no-restricted-syntax
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const originalRemove = SourceBuffer.prototype.remove;
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// eslint-disable-next-line no-restricted-syntax
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SourceBuffer.prototype.remove = function(startTime, endTime) {
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// eslint-disable-next-line no-restricted-syntax
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return originalRemove.call(this, startTime, endTime - 0.001);
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};
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}
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/**
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* Patch isTypeSupported() to reject TS content. Used to avoid TS-related MSE
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* bugs on Safari.
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*
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* @private
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*/
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static rejectTsContent_() {
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const originalIsTypeSupported = MediaSource.isTypeSupported;
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MediaSource.isTypeSupported = (mimeType) => {
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// Parse the basic MIME type from its parameters.
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const pieces = mimeType.split(/ *; */);
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const basicMimeType = pieces[0];
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const container = basicMimeType.split('/')[1];
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if (container.toLowerCase() == 'mp2t') {
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return false;
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}
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return originalIsTypeSupported(mimeType);
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};
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}
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/**
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* Patch |MediaSource.isTypeSupported| to always reject |codec|. This is used
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* when we know that we are on a platform that does not work well with a given
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* codec.
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*
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* @param {string} codec
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* @private
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*/
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static rejectCodec_(codec) {
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const isTypeSupported = MediaSource.isTypeSupported;
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MediaSource.isTypeSupported = (mimeType) => {
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const actualCodec = shaka.util.MimeUtils.getCodecBase(mimeType);
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return actualCodec != codec && isTypeSupported(mimeType);
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};
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}
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/**
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* Patch isTypeSupported() to chain to a private API on the Chromecast which
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* can query for support of detailed content parameters.
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*
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* @private
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*/
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static patchCastIsTypeSupported_() {
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const originalIsTypeSupported = MediaSource.isTypeSupported;
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MediaSource.isTypeSupported = (mimeType) => {
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// Parse the basic MIME type from its parameters.
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const pieces = mimeType.split(/ *; */);
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pieces.shift(); // Remove basic MIME type from pieces.
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const hasCodecs = pieces.some((piece) => piece.startsWith('codecs='));
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if (!hasCodecs) {
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// Though the original reason for this special case was not documented,
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// it is presumed to be because the platform won't accept a MIME type
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// without codecs in canDisplayType. It is valid, however, in
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// isTypeSupported.
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return originalIsTypeSupported(mimeType);
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}
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// Only canDisplayType can check extended MIME type parameters on this
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// platform (such as frame rate, resolution, etc).
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// In previous versions of this polyfill, the MIME type parameters were
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// manipulated, filtered, or extended. This is no longer true, so we pass
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// the full MIME type to the platform as we received it.
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return cast.__platform__.canDisplayType(mimeType);
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};
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}
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/**
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* Patch isTypeSupported() to translate vp09 codec strings into vp9, to allow
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* such content to play on older smart TVs.
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*
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* @private
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*/
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static patchVp09_() {
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const originalIsTypeSupported = MediaSource.isTypeSupported;
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if (shaka.util.Platform.isWebOS()) {
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// Don't do this on LG webOS as otherwise it is unable
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// to play vp09 at all.
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return;
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}
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MediaSource.isTypeSupported = (mimeType) => {
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// Split the MIME type into its various parameters.
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const pieces = mimeType.split(/ *; */);
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const codecsIndex =
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pieces.findIndex((piece) => piece.startsWith('codecs='));
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if (codecsIndex < 0) {
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// No codec? Call the original without modifying the MIME type.
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return originalIsTypeSupported(mimeType);
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}
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const codecsParam = pieces[codecsIndex];
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const codecs = codecsParam
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.replace('codecs=', '').replace(/"/g, '').split(/\s*,\s*/);
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const vp09Index = codecs.findIndex(
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(codecName) => codecName.startsWith('vp09'));
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if (vp09Index >= 0) {
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// vp09? Replace it with vp9.
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codecs[vp09Index] = 'vp9';
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pieces[codecsIndex] = 'codecs="' + codecs.join(',') + '"';
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mimeType = pieces.join('; ');
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}
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return originalIsTypeSupported(mimeType);
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};
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}
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};
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shaka.polyfill.register(shaka.polyfill.MediaSource.install);
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